1. Field of the Invention
This invention relates to valves and in particular to multiple blade air damper valves or air dampers.
2. Prior Art Statement
Multiple blade air dampers are widely used in industry in association with fan systems of all types. Multiple blade air dampers may be of the so-called parallel blade type wherein a plurality of air flow control blades are rotated in the same direction of rotation to control the positions thereof. In addition, such multiple blade air dampers may be of the so-called opposed blade type wherein alternate air flow control blades are rotated in opposite directions to control their positions.
Opposed blade air dampers are employed where it is desired to provide a more even distribution of air flow downstream of the damper. However, opposed blade dampers proposed heretofore do not provide optimum air flow distribution throughout the flow area thereof.